Symmetry-Enriched Topological Phases and Their Gauging: A String-Net Model Realization

Fuente: arXiv
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Main Authors: Fu, Nianrui, Zhao, Yu, Wan, Yidun
Format: Preprint
Published: 2025
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author Fu, Nianrui
Zhao, Yu
Wan, Yidun
author_facet Fu, Nianrui
Zhao, Yu
Wan, Yidun
contents We present a systematic framework for constructing exactly-solvable lattice models of symmetry-enriched topological (SET) phases based on an enlarged version of the string-net model. We also gauge the global symmetries of our SET models to obtain string-net models of pure topological phases. Without invoking externally imposed onsite symmetry actions, our approach promotes the string-net model of a pure topological order, specified by an input unitary fusion category $\mathscr{F}$, to an SET model, specified by a multifusion category together with a set of isomorphisms. Two complementary construction strategies are developed in the main text: (i) promotion via outer automorphisms of $\mathscr{F}$ and (ii) promotion via the Frobenius algebras of $\mathscr{F}$. The global symmetries derived via these two strategies are intrinsic to topological phases and are thus termed blood symmetries, as opposed to adopted symmetries, which can be arbitrarily imposed on topological phases. We propose the concept of symmetry-gauging family of topological phases, which are related by gauging their blood symmetries. With our approach, we construct the first explicit lattice realization of a nonabelian-symmetry-enriched topological phase -- the $S_3$ symmetry-enriched $\mathbb{Z}_2 \times \mathbb{Z}_2$ quantum-double phase. The approach further reveals the role of local excitations in SET phases and establishes their symmetry constraints.
format Preprint
id arxiv_https___arxiv_org_abs_2508_08245
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Symmetry-Enriched Topological Phases and Their Gauging: A String-Net Model Realization
Fu, Nianrui
Zhao, Yu
Wan, Yidun
Strongly Correlated Electrons
Statistical Mechanics
High Energy Physics - Theory
Mathematical Physics
We present a systematic framework for constructing exactly-solvable lattice models of symmetry-enriched topological (SET) phases based on an enlarged version of the string-net model. We also gauge the global symmetries of our SET models to obtain string-net models of pure topological phases. Without invoking externally imposed onsite symmetry actions, our approach promotes the string-net model of a pure topological order, specified by an input unitary fusion category $\mathscr{F}$, to an SET model, specified by a multifusion category together with a set of isomorphisms. Two complementary construction strategies are developed in the main text: (i) promotion via outer automorphisms of $\mathscr{F}$ and (ii) promotion via the Frobenius algebras of $\mathscr{F}$. The global symmetries derived via these two strategies are intrinsic to topological phases and are thus termed blood symmetries, as opposed to adopted symmetries, which can be arbitrarily imposed on topological phases. We propose the concept of symmetry-gauging family of topological phases, which are related by gauging their blood symmetries. With our approach, we construct the first explicit lattice realization of a nonabelian-symmetry-enriched topological phase -- the $S_3$ symmetry-enriched $\mathbb{Z}_2 \times \mathbb{Z}_2$ quantum-double phase. The approach further reveals the role of local excitations in SET phases and establishes their symmetry constraints.
title Symmetry-Enriched Topological Phases and Their Gauging: A String-Net Model Realization
topic Strongly Correlated Electrons
Statistical Mechanics
High Energy Physics - Theory
Mathematical Physics
url https://arxiv.org/abs/2508.08245